In short
Last Writings on the Philosophy of Psychology are two volumes of manuscript remarks from 1948-1951, edited by von Wright and Nyman (1982, 1992). Volume I is the source of much of Part II of the Philosophical Investigations; Volume II, The Inner and the Outer, examines how we know what others feel.
Last Writings on the Philosophy of Psychology (Letzte Schriften über die Philosophie der Psychologie) is the name for two volumes of late manuscript remarks on the mind: on seeing, meaning, believing, pretending and knowing what someone else feels. Volume I covers October 1948 to March 1949, most of it written in Dublin. Volume II, subtitled The Inner and the Outer, covers 1949 to 1951. G.H. von Wright and Heikki Nyman edited both; the bilingual editions appeared with Blackwell in 1982 and 1992, translated by C.G. Luckhardt and Maximilian A.E. Aue.
What these volumes are
They are not books Wittgenstein planned. They are the manuscripts from which he drew, or might have drawn, finished work. Volume I is the more important for scholars: it is the notebook from which Wittgenstein selected more than half of the remarks for what was published as Part II of the Philosophical Investigations, now often called "Philosophy of Psychology: A Fragment". The German edition carries the telling subtitle Vorstudien zum zweiten Teil der Philosophischen Untersuchungen, preliminary studies for that second part.
Volume II gathers remarks from the following two years, from notebooks that also contain material for On Certainty and the remarks on colour. Together with the two volumes of Remarks on the Philosophy of Psychology (1946-1948), they form one long, continuous investigation of psychological concepts.
What they say
Volume I returns again and again to seeing aspects: the moment a drawing suddenly looks like a duck instead of a rabbit, or a face reminds you of someone. What changes, if nothing in the picture does? From there Wittgenstein moves to the experience of meaning. When you say a word on its own and it "sounds" like its meaning, is that experience part of what the word means? He imagines a person who is "meaning-blind", who uses words perfectly but lacks this experience, and asks what such a person would miss. Other remarks deal with belief and Moore's paradox: the oddness of saying "it is raining, but I do not believe it", a sentence that may be true but cannot sensibly be asserted.
Volume II turns to the relation between inner and outer. We often say that another person's feelings are hidden from us. Wittgenstein does not deny the uncertainty, but he changes its description. The inner is not concealed behind behaviour the way an object is concealed behind a screen. Our uncertainty about other people is a feature of our psychological concepts themselves: they are applied to patterns that recur in a life with endless variations, and they rest on what he calls imponderable evidence, the glance, the tone, the subtle shift of a face. Pretending, too, is a pattern that has to be learned before it can be recognised.
How to read them
These are working notebooks: repetitive, tentative, sometimes brilliant on a single page. Read Part II of the Investigations first, then dip into Volume I to see how its remarks were born and what was left out. Volume II reads well alongside On Certainty, since both ask how far doubt can sensibly reach. The University of Chicago Press edition of Volume I and the Wiley-Blackwell edition of Volume II keep German and English on facing pages. The manuscripts themselves are available in the Bergen Nachlass Edition.
Why they matter
For a long time these volumes were treated as material for specialists, and that is still largely what they are. But they show the late philosophy of mind in more detail than anything Wittgenstein finished. Scholars such as Joachim Schulte have used them to argue that the late work is not behaviourism in disguise: the point is not that the inner is nothing but behaviour, but that our concepts of the inner are woven into our lives with others. Others find in them the roots of later debates on other minds and the expression of emotion. The Stanford Encyclopedia entry on Wittgenstein places them in the late period.
Verdict
Read these if the philosophy of psychology in the Investigations has gripped you and you want to watch it grow, or if you are writing on aspect-seeing, meaning-experience or other minds. They reward patience with flashes of real insight. Leave them aside if you are new to Wittgenstein: without the finished texts as a map, the notebooks are easy to get lost in.
Frequently asked questions
How do the Last Writings relate to the Philosophical Investigations?
Volume I (1948-1949) is the manuscript from which Wittgenstein selected more than half of the remarks for Part II of the Investigations, now often titled 'Philosophy of Psychology: A Fragment'. Reading both side by side shows what he kept and what he dropped.
What is 'The Inner and the Outer'?
It is the subtitle of Volume II (1949-1951). It refers to the relation between mental states and behaviour, and to Wittgenstein's claim that our uncertainty about other people's feelings belongs to our psychological concepts rather than to a hidden inner object.
Are these volumes difficult?
Yes, mainly because they are unfinished notebooks without an argument laid out for the reader. They are best read after the Investigations, by readers who already know the themes.
Sources
wittgenstein.be, “Last writings on the philosophy of psychology”, https://wittgenstein.be/en/books/last-writings-on-the-philosophy-of-psychology/ (2026-10-20)